1. Field of the Invention
The invention relates to an electromagnetic shielding device, more particularly to a multi-cavity electromagnetic shielding device.
2. Description of the Related Art
FIGS. 1 and 2 illustrate an electronic device employing a conventional electromagnetic shielding device that includes a metal frame 1 and a metal cover 2. The metal frame 1 is mounted on a circuit board 3 via a looped solder pad unit 31 using surface mounting techniques. The circuit board 1 is mounted with first and second electronic component units 301, 302 that are spaced apart from each other, wherein the first electronic component unit 301 has a height greater than that of the second electronic component unit 302. The metal frame 1 has a looped surrounding wall configured with an inner space 103 that is divided by a partition wall 12 into a first space portion 101 for receiving the first electronic component unit 301, and a second space portion 102 for receiving the second electronic component unit 302. The metal cover 2 is mounted on the circuit board 3, and covers the metal frame 2. The metal cover 2 has a top wall 201 disposed on a top side of the metal frame 1, and a looped surrounding wall 202 extending downwardly from a periphery of the top wall 201 and disposed in proximity to the looped surrounding wall 11 of the metal frame 1 such that the metal frame 1 cooperates with the metal cover 2 so as to define first and second cavities corresponding respectively to the first and second space portions 101, 102.
It is noted that, since the metal cover 2 is formed by pressing, it is difficult to fabricate the metal cover having various thicknesses, and various heights relative to the circuit board 3. As a result, even though the heights of the first and second electronic component units 301 and 302 are different, the metal cover 2 of the conventional electromagnetic shielding device has a uniform height (h), such as 2 mm, and a thickness ranged from 0.15 mm to 0.2 mm. Therefore, the electronic device employing the conventional electromagnetic shielding device has a relatively large size, thereby impeding miniaturization of the electronic device.